Slot cutting device



April 25, 1950 J. G. SCHOTTHOEFER SLOT CUTTING DEVICE Filed Dec. 1, 1947 I N VEN TOR. (/0465 dciozl/koe fer ?atented Apr. 25, 1950 lTE stares ears! FFICE This invention relates to a slot cutting device.

The invention is particularly concerned with a hand operable slot cutting device in the gem of an attachment, and is adapted for detachable connection with various metal workingfnachihes as an economical substitute for the expensive power-operated slotting machines used in the larger machine shops."

A primary object of the invention is to provide a hand operable slot cutting device which is adapted for detachable connection with the tool rest" of a lathe or other metal working machine for the cutting of keys'eats arid the like as occasion may demand such an operation on any icularpiecepf'work.

further object of vthe invention .is to provide a hand operable slot cutting device 111 ;111:1 ing: reciprocable cylindrical 'tool 'carrving rain and operating connections for warm cesi s e i when sa r e a ns on t axis, whereby the use of a cooperating key and slot for such purpose is avoided.

A still further object of the invention is to provide ahand operableslot cutting device which includes adjustable and lubricated partelfor maximum eiliciency in operation.

" A still furth r objec the invention is to provide a hand operable slot cuttingldevicewhich is relatively simple in construction andlwhich Q use in small machine shops wherein the ratherexpensive power-operated slotting machines in many instances lwould belprohibitive. Other objects and advantages of the invention will become apparent in the 'course'of the followin detailed description, taken in connection with the accompanyingdrawing wherein Figure 1 is a top plan view of the'device in accordance with a preferred embodiment thereof, the operating leverbeing shown broken away.

Figure -2 is a side elevational view of the 'device, with .the operating-lever broken away.

Figure 3' is a transverse sectional view in the plane of line 3-3 ori Figure 2.

Figure'A is a top plan view of the supporting base in the device.

Figure 5 is a fragmental vertical sectional-view in the planes of line'5 -5 on Figure l.

Figure G is a plan view of one of the-bearing washers used in certain pivot joints.

Figure 7' is a planview'of c eer the thrust we h' r u e ii jle e eie time i a tatisti siti qee e ie it e reces i ii elishes m thrust washer in the plane o t line 8-8 on Fig- Figure 9 is a broken side elevational view of one of the bolts used in the pivot joints! Figure 10 is a views: the bolt shown; in Fi ure as observed from the right thereof. Figure 11 is' a "fragmentary "longitudinal sec ties-an an enlarged scale and aisaosm in narticular the adjustable afd 'i'eleasableconnection between the min and tow- 'bar'."

Pleierdng now detail to the drawing, i8 designates a basewhich" 'is provided with' an elongated slot I man a split vertically disposed sleeve E2 is unitary with one end of thebalsel The sleeve isprovlded with' iu'gs'last opp'ssite sidesof the split therein and ass st, u; is en: gfaged in" such lugs 'fo'r'contra'cting the slee've.""

The base I!) is adapted for dispositionlbn a tool Tes't'l't of a"la'theor othernietal "working machine, and the base isrefnbvably retained in position on the toolrest by means of a T- head'ed bolt 55, as is clearly shown iii Fig'ure 2.

The cylindrical vertical column 'l'Boi a tubular body Irlhi'be'i 11' 1'5 Vertically "adjustably Sup ported in the'sleeve L2as'by'rrieans of the bolt M. The tubular body H '-isftrafisvei'sely slit a satstantialfdistan'ceiroin eacfl endthereof; as i'n'dl cated ll 8; "-The slits" extend through the" wall of the body throughout arfangular range of. 1'80? and with the tsrmmasaf the ,s1itsdisposedin vertical diameters offlthe body. The body is fh rther longitudinally slit at 29, such slits being" at "the lowefside of tlie'body and extending from the free ends thereof to the slits il 'The slits 5-8 and 26 thus provide yieldable end p01 tion e, which are'p'rovided withdugs 2! on oppn; site'sides of the'slits Z Mand screws 22 cooperate with the lugs or contracting the yieldable sleeve t. it t, a .y m t 1 A split bushing 23, of bronze or the like, is

disposed within each sleeve menu rovides ad j ustable bearings for' the opposite snasor a chisel-warren which is adapted forreci'prdcation.'irithe'btidyl'l'.

The forward end fthe ram 213 is provided with an elongated cylindrical recess? 5 which; has forward asset aceta e as hich e 1 dtw r it i-wi d d niid in h p vi i a 111l11r 15" he i adapted to reiiiovably and adjustably re 2e, andfor the purposeofa justing and retainingthe tool ar in: tlie'recessthe e lq i tr 9turefi eroii,dest

A block 21 is" removal) dispo shoulder 25 by means of a set screw 21'. An adjustable stop in the form of a long screw 21" is axially disposed within the recess and is threaded. through a threaded aperture in the block 21. The rear end of the tool bar 26 bears against the outermost end of the screw for limiting movement of the tool bar within the recess, whereby a single tool bar of predetermined length may be used for different cutting jobs. The forward end of the screw is slotted as shown for adjusting same with a screw driver or the like, and the rear end of the screw is provided with a head 2'1 which will abut the block 21 and prevent outward adjustment of the screw to an extent such that the tool bar has insufficient bearing in the recess. The recessed end of the ram is in fact a holding chuck and for this purpose the free end of the ram is beveled as indicated and threaded for the reception of a. clamping nut 28, which also functions as a stop for limiting rearward movement of the ram in the body H.

In order to provide for an effective gripping action of the recessed ram on the tool bar, the end of the ram is provided with a plurality of slots 24' which may preferably be four in number, as shown, and which extend a substantial distance from the extremity of the ram in the direction of its length, thereby providing yieldable segments between the slots for frictionally gripping the tool bar when the nut 28 is drawn up.

To effect an adjustment whereby to change the length of the tool bar externally of the ram, the nut 23 is loosened and the bar is removed, after which the accessible screw is adjusted by threading same one way or the other in the block 27. The tool bar is then re-inserted and the nut 28 drawn up.

A cuttin tool 29 is removably seated in an aperture adjacent the free end of bar 23 and is retained in position by a screw 30.

A second stop collar 31 is provided for limiting forward movement of the ram in the body, and this collar is split and is secured to the ram rearwardly of thebody by means of a screw 32.

From the above, it will be seen that the ram is slidably supported within the tubular body H in the absence of any means for restraining rotation of the ram about its axis.

It is, of course, essentialthat the ram have a rectilinear movement only and that it be restrained against rotation about its axis in order to provide a straight sided slot as effected by the cutter 23. While this rectilinear movement may be efiected by the provision of the usual means in the form of a key and cooperating key way, such is subject to rapid wear, and as looseness develops between the key and key way, the ram is free for limited rotation about its axis, with the result that the cutting tool is given a wavy movement with a corresponding wall on the groove being cut.

In the present invention the ram is reciprocated by means of a link-and-lever structure havin pivot joints of such form as to avoid rotation of the ram about its axis.

The operating means for the ram comprises a link 33 and a lever 34 having an actuating handle 35. The link is pivotallyv connected at one end thereof to the body I] by means of a pivot joint 36, the link 33 and lever 34 being pivotally connected together by means of a pivot joint 3': and the lever 34 being pivoted intermediate its ends to the ram 24 by a pivot joint 38.

Each of the pivot joints comprises a thrust washer 39 and a pair of bearing washers 49.

These washers are of relatively large diameter 4 and they all lie in horizontal planes in the assembled joints, the washers in the joints 36 and 31 being in common planes and those in joint 38 being in planes parallel with those containing the washers of joints 36 and 31.

Each of the joints includes a pivot bolt 4| and a cooperating clamp nut 42.

Each of the bolts has a relatively long smooth shank portion and is screw-threaded at its lower end only, and such screw-threaded end in joint 36 has screw-threaded engagement with a boss 43 on body H, the screw-threaded end in joint 31 has screw-threaded engagement with lever 34, and the screw-threaded end in joint 38 has screwthreaded engagement with the flattened end portion 45 of ram 24.

The thrust washers 39 are uppermost in the joints and are each provided with an oil hole 56. The bearing washers 40 are disposed on opposite sides of link 33 in joints 35 and 31 and on opposite sides of lever 34 in joint 38, and each of these washers is provided with a plurality of oil-distributing holes 41.

Each thrust washer 39 is provided with a slot 48 in its upper face, and such slot has a downwardly and inwardly beveled side wall.

The head of each pivot bolt 4! is provided with opposite parallel tapered portions 49 which engage the beveled walls of slots 48 whereby relative rotation of the thrust washers and bolts about the axes thereof is prevented, for the reason that considerable wear would result if the relatively small bolt heads rotated relative to the thrust washers.

From the above, it will be seen that only the bearing washers 40 and the link or lever disposed therebetween have rotation relative to the bolt 4 I, and since the washers are of relatively large diameter and by means of the oil holes the contactlng surfaces are well lubricated, little wear from friction can occur. The bolts 4| are drawn up to maintain the washers in firm engagement, whereby the link 33 and lever 34 are constrained to move in horizontal planes, and since the joint 38 is on the ram it is effectively restrained against the bolts 4| may be tightened and the clamp nuts 42 drawn up to retain the adjustment.

Should the ram become loose in the body I! the screws 22 may be tightened to draw the bushings 23 into firm bearing engagement with the ram.

It should be appreciated from the foregoing disclosure that a slot-cutting attachment is provided by the present invention which is extremely simple in construction, is readily attachable to the work rest of a metal-working machine, and which is provided with manually operating means which confine the tool-carrying ram to movement along its axis only.

While I have disclosed my invention in accordance with a single specific embodiment thereof, such is to be considered as illustrative only, andnot restrictive, the scope of the invention being defined in the following claims.

What I claim and desire to secure by U. S. Letters Patent is: i

1. A slot-cutting attachment comprising a base for removable connection with the tool restmember for axial reciprocation therein, a boss on said body member adjacent the front end thereof, a flattened po' tion on said ram adjacent the rear end thereof, a horizontally disposed relatively wide link having one end thereof movably connected with said boss by a pivot joint, a horizontally disposed relatively wide lever movably connected intermediate its ends to said fiattened portion of the ram by a pivot joint, and the link and lever being movably connected at adjacent ends thereof by a pivot joint.

2. The structure according to claim 1, together with adjustable bearings for said ram disposed adjacent opposite ends of said body member.

3. The structure according to claim 1, wherein said link is disposed above the body member and wherein said lever is disposed between the link and body member and is provided with an operating handle.

4. The structure according to claim 1, wherein the forward end of said ram is provided with a cylindrical recess, a cutting tool bar having one end thereof removably and adjustably disposed within said recess, an adjustable stop within the recess for limiting movement of the bar there- Within, and clamping means on the free end of the ram for frictionally retaining the bar in any adjusted position within the recess.

5. The structure according to claim 1, wherein each of said pivot joints comprises a vertically disposed bolt having the free end portion of its shank threaded and locked against rotation in one of the parts connected, the shank of the bolt between said threaded portion and the head thereof extending freely through another of the parts connected, a thrust washer beneath the head of the bolt and locked thereto to prevent relative rotation between the washer and bolt, and a bearing washer loosely surrounding the last-named shank portion and disposed on each side of the other part connected.

6. A manually operable slot-cutting device comprising a base for detachable connection with the tool rest of a metal working machine, a horizontally disposed tubular body member supported by the base, a cutting tool operating ram disposed within the body member for reciprocatory movement, operating means for the ram comprising a horizontal link and a horizontal lever, a pivot joint connecting one end of the link with the body member, a pivot joint interconnecting the link and lever, and a pivot joint connecting the lever with the ram, said pivot joints each including a vertically disposed pivot bolt and a plurality of relatively large horizontally disposed washers for maintaining the link and lever in horizontal planes in operation and for preventing rotation of the ram about its axis.

'7. A manually operable slot-cutting device comprising a base for detachable connection with the tool rest of a metal working machine, a horizontally disposed tubular body member supported by the base, a cutting tool operating ram disposed within the body member for reciprocatory movement, and manually operable means connected with the body member and the ram for reciprocating the latter, the said body member being supported by the base by means of a vertically disposed cylindrical column depending from the body member, an adjustable sleeve on the base receiving said column in adjusted positions thereof, and screw means for tightening the sleeve about the column in any adjusted position thereof.

JOSEPH G. SCI-IOTTHOEFER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,123,788 McNaughton July 12, 1938 2,263,870 Currie Nov. 25, 1941 2,303,106 Baurhenn Nov. 24, 1942 2,355,324 Palmer Aug. 8, 1944 

